<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            background-color: pink;
            width: 200px;
            height: 200px;
            border: 1px solid;
        }
        
        .box>div {
            width: 50px;
            height: 50px;
            background-color: blue;
        }
    </style>
</head>

<body>
    <div class="box">
        <div></div>
    </div>
</body>

</html>